Cast attribute values to string before publishing to MQTT (#9872)

* Cast attribute values to string before publishing to MQTT

* Simplify

* Use JSON serialization, add test

homeassistant/components/mqtt_statestream.py

@@ -5,6 +5,7 @@ For more details about this component, please refer to the documentation at
 https://home-assistant.io/components/mqtt_statestream/
 """
 import asyncio
+import json
 
 import voluptuous as vol
 
@@ -12,6 +13,7 @@ from homeassistant.const import MATCH_ALL
 from homeassistant.core import callback
 from homeassistant.components.mqtt import valid_publish_topic
 from homeassistant.helpers.event import async_track_state_change
+from homeassistant.remote import JSONEncoder
 import homeassistant.helpers.config_validation as cv
 
 CONF_BASE_TOPIC = 'base_topic'
@@ -65,8 +67,9 @@ def async_setup(hass, config):
         if publish_attributes:
             for key, val in new_state.attributes.items():
                 if val:
+                    encoded_val = json.dumps(val, cls=JSONEncoder)
                     hass.components.mqtt.async_publish(mybase + key,
-                                                       val, 1, True)
+                                                       encoded_val, 1, True)
 
     async_track_state_change(hass, MATCH_ALL, _state_publisher)
     return True

tests/components/test_mqtt_statestream.py

@@ -127,7 +127,11 @@ class TestMqttStateStream(object):
         # mqtt_statestream state change on initialization, etc.
         mock_pub.reset_mock()
 
-        test_attributes = {"testing": "YES"}
+        test_attributes = {
+            "testing": "YES",
+            "list": ["a", "b", "c"],
+            "bool": True
+        }
 
         # Set a state of an entity
         mock_state_change_event(self.hass, State(e_id, 'off',
@@ -138,7 +142,11 @@ class TestMqttStateStream(object):
         calls = [
             call.async_publish(self.hass, 'pub/fake/entity/state', 'off', 1,
                                True),
-            call.async_publish(self.hass, 'pub/fake/entity/testing', 'YES',
+            call.async_publish(self.hass, 'pub/fake/entity/testing', '"YES"',
+                               1, True),
+            call.async_publish(self.hass, 'pub/fake/entity/list',
+                               '["a", "b", "c"]', 1, True),
+            call.async_publish(self.hass, 'pub/fake/entity/bool', "true",
                                1, True)
         ]